WASHINGTON -- The director of the FBI has confirmed ongoing investigations into communications between Russian officials and President Donald Trump's aides.

James Comey made the statement on March 20 at a hearing of the House Intelligence Committee, one of several congressional investigations into Russian actions during the 2016 U.S. presidential election campaign.

During its first two months in office, the Trump administration has been dogged by intelligence reports of Russia's alleged meddling and by press reports that the FBI was investigating Trump's associates.

In his opening remarks, Comey confirmed to the House committee that such investigations were ongoing.

"And that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government and whether there was any coordination between the campaign and Russia's efforts," Comey said.

The FBI director also said neither he nor the U.S. Justice Department had any information supporting Trump's allegations that his private offices in New York had been wiretapped by his predecessor, President Barack Obama.

Trump made the extraordinary assertion in a posting to Twitter on March 4.

"I have no information that supports those tweets and we have looked carefully inside the FBI," Comey said. "The Department of Justice has asked me to share that the information is the same for the department and all its components."

At the hearing, Republican committee Chairman Devin Nunes joined Democratic Representative Adam Schiff in saying there was "no physical wiretap" of Trump’s offices. But Nunes suggested there might have been other types of ongoing surveillance.

The House committee is one of at least five congressional committees looking into alleged Russian meddling and influence efforts during the 2016 election.

Meanwhile, U.S. National Security Agency (NSA) Director Mike Rogers on March 20 strongly rebutted another allegation suggested in recent days by officials in the Trump administration -- that the NSA had asked its British counterpart, the GCHQ, to spy on Trump.

That suggestion has roiled historically close ties between Washington and London, with British officials calling it absurd, and the usually taciturn GCHQ issuing an extraordinary statement to refute the allegation.

"That would be expressly against the construct of the 'Five Eyes' agreement that's been in place for decades," Rogers told the committee, referring to an intelligence-sharing agreement between the United States, Australia, Canada, New Zealand, and Britain.

U.S. intelligence agencies released a report in January saying they assessed that Russian President Vladimir Putin ordered an "influence campaign" to interfere in the presidential election.

The report said the Russian campaign aimed to use computer hacks, leaks, and other methods to undermine faith in the U.S. electoral system and denigrate Democratic candidate Hillary Clinton.

The report also concluded Russia developed a clear preference for Trump.

Russia has denied any attempts to sway the November 8 vote and Trump has rejected suggestions that he or his campaign had improper contacts with Russian officials.

Trump repeated those denials in a series of Twitter posts published hours before the March 20 House hearing began.

"The Democrats made up and pushed the Russian story as an excuse for running a terrible campaign," he wrote.

"The real story that Congress, the FBI and all others should be looking into is the leaking of Classified information," Trump said in a subsequent tweet. "Must find leaker now!"

As the hearing continued, the White House sent out another post on Twitter, insisting that the testimony from Comey and Rodgers showed that Russia did not influence the U.S. election campaign. Comey and Rogers did not say that.

Trump forced Michael Flynn out as national security adviser in February after it was revealed that Flynn misled Vice President Mike Pence and other White House officials about his conversations in December with the Russian ambassador to the United States, Sergei Kislyak.

That was followed by accusations that Attorney General Jeff Sessions misled senators by saying during his confirmation hearing that he did not meet with any Russian government official during the campaign.

Sessions later admitted meeting with Kislyak at least twice, and has recused himself from the investigation. As attorney general, Sessions is the head of the Justice Department and has oversight of the FBI.

Democratic lawmakers have been eager for Comey to make a clear statement debunking Trump’s wiretap claims after lawmakers from both the Republican and Democratic parties said on March 19 that they had yet to see evidence supporting Trump’s claim.

Republicans, meanwhile, have sought to broaden the focus of attention to include leaks of classified information to U.S. media.

The confirmation by Comey that an FBI investigation was under way as early as July 2016 into possible links between Trump aides and Russian officials has prompted frustrated statements from former members of Clinton’s presidential campaign.

In late October, shortly before the November 8 vote, Comey publicly confirmed that the FBI was looking at files found on a laptop belonging to a top Clinton aide to see if the material was classified and had been improperly handled.

The FBI typically does not disclose an ongoing criminal probe of any sort. Coming in the midst of a heated election campaign, Comey’s statement about the Clinton aide’s computer was criticized by some as political interference.

Comey later said FBI agents found no evidence of illegal activity. But the disclosure of the probe cast a cloud over the final days of Clinton's campaign. Some of her supporters say it helped tilt the election in favor of Trump.